a) Field of the Invention
The invention is directed to a spring-loaded catch or snap lock for a sliding door or the like of a machine casing or the like, which sliding door is preferably reinforced on at least one side by a sheet metal fold or a hollow rectangular section or profile, wherein the lock is mounted in a receiving space formed by the sheet metal fold or hollow rectangular profile, with a handle which is swivelably mounted at the reinforced side of the sliding door and which cooperates with a latch bolt device, and with a retaining device for receiving the latch bolt when the door is closed, this retaining device being arranged on or accommodated in a door frame or a profile defining an opening in the machine casing.
b) Description of the Related Art
Snap locks of the type mentioned above are already known to the present Applicant. The known arrangement is disadvantageous, among other reasons, because a latch handle that must be swiveled for opening is normally utilized for opening the snap lock, whereupon the lock is released and the sliding door can be slid open by continued pressing against the latch handle. This latch handle has the disadvantage that clothing can catch on it, which cannot be tolerated in dangerous situations. A further disadvantage is that the handle can be in an inclined position with respect to the sliding direction due to the swiveling process so that increased pressing force must be exerted on the latch handle and, moreover, there is a tendency for the hand to slip off the latch handle in its inclined position. A third disadvantage is the unattractive appearance of such a latch handle.
GB-A-143,192 discloses a construction corresponding to a first embodiment form of the novel lock to be described herein. This construction has a housing which is fitted into a recess formed by the door and which has, on one side, a flange resting on the door surface, while a corresponding shaped piece is arranged on the other side of the door (see page 2, lines 27-32 of this reference). Apart from the essential features mentioned above, this reference further discloses the additional features that the handle is a rod which is mounted at the ends about a swiveling axis extending parallel to the side of the door leaf provided with the recess, the ends of the rod being received in a rod holder, and that at least one of the two rod holders is coupled with a freerunning hook which is mounted so as to be swivelable about an axis extending parallel to the swiveling axis of the rod and forms the latch bolt.
FR-A-1.082.499 discloses a lock in which the axis of the hook is vertical to the swiveling axis of the rod and, to this extent, corresponds to another embodiment form of the novel lock.
Neither of these known locks is suitable for sheet metal cabinet doors. In addition, the lock in GB-A-143,192 requires that a specially shaped recess which is complicated to produce is made in the door. The lock in FR-A-1.082.499 can not be accommodated either in a hollow rectangular profile or in the fold space of sliding doors formed from sheet metal by bending.
It is the primary object of the invention to improve a snap lock of the type mentioned above in such a way that the disadvantages noted above are entirely prevented as far as possible.
The object is met according to a first embodiment of a snap lock for a sliding door in a machine casing, which sliding door is reinforced on at least one side by a sheet metal fold or a hollow rectangular profile. The lock is mounted in a receiving space formed by the sheet metal fold or hollow rectangular profile. The lock has a handle which is swiveably mounted at the reinforced side of the sliding door and which cooperates with a latch bolt device. The lock includes a retaining device for receiving the latch bolt when the door is closed. The retaining device is arranged on or accommodated in a door frame or a profile defining an opening in the machine casing. The handle comprises a bar which is supported at the ends by a swivel pin extending parallel to the reinforced side of the door leaf and located behind the door leaf or inside the sheet metal fold or hollow profile. A bar holder is provided for receiving the ends of the bar. At least one of two bar holders is coupled with a hook which is mounted so as to be swivelable coaxially to the swivel pin and has free travel and forms a lock latch. A swivel support for the bar holder is formed by a profile piece which is provided with a fastening flange and which is received in a rectangular opening in the sheet metal fold or in the hollow profile of the door leaf.
In a second embodiment, a snap lock for a sliding door in a machine casing, which sliding door is reinforced on at least one side by a sheet metal fold or a hollow rectangular profile also meets the object of the invention. The lock is mounted in a receiving space formed by the sheet metal fold or hollow rectangular profile. The lock has a handle which is swivelably mounted at the reinforced side of the sliding door and which cooperates with a latch bolt device. The lock includes a retaining device for receiving the latch bolt when the door is closed. The retaining device is arranged on or accommodated in a door frame or a profile defining an opening in the machine casing. The handle comprises a bar which is supported at the ends thereof around a swivel pin extending parallel to the reinforced side of the door leaf and located behind the door leaf or inside the sheet metal fold or hollow profile. A bar holder is provided for receiving the ends of the bar holder. At least one of two bar holders engages with a hook which is mounted around a bar vertical to the swivel pin and forms the lock latch. A bearing support for the bar holder is formed by a profile piece which is provided with a fastening flange and which is received in a rectangular opening in the sheet metal fold or in the hollow profile of the door leaf.
It is achieved by means of these two constructions, first, that there is no hook-shaped handle on which the user""s clothes can catch. Further, it is achieved that the orientation of the handle with respect to the movement direction of the sliding door does not change for the user""s hand during the process of swiveling because the handle does not rotate with respect to this direction but, rather, is only swiveled and pushed in this direction substantially parallel to the door leaf. The actuating force accordingly acts vertically to the extension of the handle and there is no danger of the hand slipping off of the handle. The handle also has a more aesthetically pleasing form and, on the whole, allows a greater force to be exerted on the sliding door in order to push it. In contrast to the references mentioned above, applicability in sheet metal sliding doors is achieved.
In the first embodiment form, the bearing support for the bar holder is formed by a section piece or profile piece which is provided with a fastening flange and which is received in a rectangular opening in the sheet metal fold or in the hollow profile of the door leaf. This is a particularly stable and attractive arrangement and enables sensible utilization of existing space in the sheet metal fold or hollow profile.
Numerous further developments having their own advantages are made possible by the snap lock according to the invention in accordance with claim 1 and claim 10.
According to a first further development of the first embodiment form, the bar holder, in the area of its bearing support, is a two-pronged fork, the hook being supported between its two prongs. This provides a bearing support which resists tilting and which is particularly stable and smoothly operating and facilitates actuation of the snap lock for automatic latch-type locking when sliding the door closed as well as when releasing and subsequently opening the lock for sliding the door open.
According to another further development of the invention, the fork web between the two fork prongs is provided with two stop faces for limiting the swiveling movement of the hook. This allows the user to determine whether or not the lock has disengaged already by opening until a certain stopping point, so that the sliding door can then be opened.
According to another further development of the invention, the profile piece forms a receptacle for a pressure spring which presses the hook into its closed position. Further, the bar holder can form a receptacle for a spring which forces the bar holder into its rest position. It is especially favorable when the spring is a pressure spring which contacts an inner surface of the profile piece. A particularly simple construction having the additional advantage of great compactness is achieved by means of this step.
The surface of the fastening flange advantageously forms a partial cylinder, wherein the bar holder forms a collar which extends at a slight distance from the flange surface and far enough so that the profile piece opening is covered by the collar during the swiveling movement of the holder. These steps prevent injury to the user.
It is also favorable that the side walls of the profile piece have bore holes which are coaxial to one another and offset relative to the swivel pin and that the hook has a bore hole which is aligned with the bore holes of the side walls when the hook is located in the locked position and the bar receptacle is in the rest position, and that a pin lock can be slid into these bore holes. A secure lock with a particularly simple design can be realized by means of these features.
In another possible further development, this pin lock can be electrically controlled. In this way, it is possible, for example, to prevent the sliding door from opening until required for reasons of security, for example, when a machine is still in operation.
There are also various further developments with respect to the above second embodiment, in which the axis of the hook does not extend coaxial to the swivel pin of the bar, but rather vertical thereto. The hook is then preferably swivelably mounted at an extension of the profile piece and is forced into its locking position, e.g., by the force of gravity. The hook can then be lifted out of this locking position, which was achieved, e.g., by force of gravity or spring force, in that the bar holder forms a cam which slides along a cam path formed by the hook and, in so doing, lifts the hook against the force of gravity when the door is to be opened and the door handle is turned for this purpose.